An
emergency call was received from a contractor installing 25,000
pound
concrete panels on a new building in San Jose, CA. The specialty
bolts being used to attach the panels were stripping out of the
nuts.
I inspected the components onsite, collected samples of the nuts
and
bolts and load tested them that day. Based on these preliminary
tests, I designed and implemented an extensive test program
within a
few days in order to quantify the variables related to the
problem
and provide detailed recommendations to remedy the deficiencies.
This
work involved statistical analysis and determination of
appropriate
safety factors.

Excavation
shoring
injury

While
disassembling an Oakland Bay Bridge excavation shoring system, a
2400
pound steel trench shield tipped over and crushed a workman
against a
concrete foundation. I found that the design and procedures were
inadequate and did not comply with the California “Construction
Safety Orders” within Title 8.

Scaffolding
failure

I
found that the engineering, structural tests and analysis of the
structural test results were inadequate in determining the safe
load
capacity of an Oakland Bay Bridge mobile scaffolding system
which
collapsed and killed a worker.

Fire
truck collision at an intersection

In
this case I installed accelerometers, external “fifth wheel”
speed pickup and brake pedal application switch for data
acquisition
during tests at the accident site. The data was recorded
continuously
by means of a laptop computer. The brake application time lag,
braking distance and stopping time were determined for a fully
loaded
fire truck.

Film
reconstruction time/position study

During
a film reconstruction of the collision of two vehicles traveling
at
highway speeds I provided and operated a data acquisition system
to
record the speeds and positions of the exemplar vehicles in the
film.

Tire
blow out

I
installed a system of valves in a tire rim in order to rapidly
deflate a tire. Using an instrumented exemplar vehicle we were
able
to repeatedly simulate a tire blow out and study the potential
for
loss of control.

Strain
gauging

A
project involved installing more than 100 strain gauges on steel
and
aluminum structural elements of a transit bus and recording
dynamic
data on actual transit routes. Strain gauges measure local
deformations (strain) within structures and the measured strains
can
be used to determine the actual compression, tension and shear
stresses in structural elements. Strain gauge rosettes were used
to
completely solve Mohr’s circle. Strain gauge measurements can
be made statically or dynamically in either the laboratory or
the
field.

Slip
and
fall

A
customer slipped and fell on a new floor in the entry of a
restaurant
on a rainy evening. I measured the slip resistance of the floor
and
found it to be slippery when wet. I reviewed construction
documents
from the contractor and the architect and found that the
property
owner had reason to believe that he had purchased a slip
resistant
flooring system.

Sidewalk
tripping
hazard

A
sidewalk was repaired after a pedestrian tripped and fell on a
vertical offset in the walkway surface. Since the defect no
longer
existed, I used snapshots taken at the time of the accident and
photogrammetry techniques to determine the dimensions of the
original
offset.

Construction
and
design defects in buildings

Physical
inspections of structural elements were performed and inadequate
nailing of shear walls and other defects were found. Review of
design
documents found inadequate structural detailing and errors in
structural calculations. Plaintiff and defense experts worked
together to develop a consensus in regard to both the extent of
the
defects and the required repairs.

Shear
wall tests

A
series of full scale plywood and gypsum wallboard walls were
constructed and tested to determine the energy absorbing and
strength
capacity of various shear wall assemblies during seismic events.

Light
rail fastener fatigue load tests

I
designed, built and operated a test system for elastomeric pads
designed to attach rails to concrete. Loads of up to 24,000
pounds
were applied for as many as 3 million cycles.

Tire
mounted on oversize rim

15
inch tires were mounted on 15.5 inch rims resulting in failure
of the
steel bead and explosion of the tire. Tire pressure was
documented
and the explosion videotaped. During the tests, the tires are
explosively launched at speeds on the order of 100 miles per
hour
with massive destructive force.

Tire
exploded with flat repair product

This
case involved a repair shop worker who attempted to repair a
pinhole
in a tire rim with a welder. In our tests, a tire was filled
with a
canned, pressurized flat repair product containing
propane/butane. A
spark was triggered inside the tire and the fuel and air mix
inside
the tire exploded destroying the tire and launching the rim at
high
energy.

Balcony
fall

A
woman stepped outside onto a third floor balcony for a cigarette
with
a friend. She leaned on the railing which failed and she fell to
her
death. I inspected the accident site to determine code
compliance and
condition of the railing.

Antenna
tower

A
research company had a wooden, non electromagnetic interference
tower
designed and constructed to support a satellite communication
dish.
The tower was found to vibrate excessively and I was brought in
to
assess the problem and design repairs.

Rocket
propellant processing facility

I
was asked to evaluate the structural condition of a concrete
blast
resistant structure which had been out of service for several
years.
The company wanted to reactivate the solid propellant grinders
in the
tower and wanted to know if the exposure to caustic chemicals,
weather and time had rendered it unsafe.

Fire
resistance of GFRC

I
coordinated the construction, instrumentation and testing of a
full
scale GFRC (glass fiber reinforced concrete) architectural
exterior
wall assembly for fire resistance.

Panel
design

I
provided the architectural cladding system structural design and
details for a building located at Wilshire Boulevard and Palm
Avenue
in Los Angeles. The cladding system is lightweight GFRC with an
unusual seismic resistant structural system.

Wheelchair
accident

A
wheel chair went out of control inside a San Francisco airport
jet
way. There being no aircraft present at the time, the occupant
of the
wheel chair fell from the jet way to the concrete apron. A wheel
chair was instrumented and tested at the site. I provided the
instrumentation and drove the wheel chair during investigative
testing.

Water
tower fall

A
workman climbing a water tower claimed he fell from the ladder
when
the hydraulic surge from a starting pump shook the tower. I
climbed
the tower with accelerometers and a computer in order to measure
and
record the intensity and frequency content of the vibrations.

Cable
car collision

I
investigated an accident involving an automobile making a left
turn
in front of a cable car. I studied the starting and stopping
capabilities of a cable car, the control systems linking the
cable
cars to the traffic signal lights and the acceleration of an
exemplar
automobile. A film reconstruction was conducted. The film
reconstruction was performed in real time since cable cars have
only
one speed.

Bicycle
accident on Haleakala

A
bicyclist lost control in a corner while descending the mountain
on a
rental bicycle and was run over by an ascending bus. Riding an
exemplar bicycle from the rental company, I investigated the
speed
and cornering capabilities of the bicycle at the accident site.
I
later instrumented the bicycle to measure the braking
capabilities
considering variables such as wet roads, front brake
application,
rear brake application and body position. I also preformed tests
to
demonstrate the stability of the bicycle.

Chair

A
customer was injured when a chair collapsed at a shopping mall
food
court. I tested exemplar chairs for stability, strength and
compliance with applicable standards.

Low
speed crash

After
instrumenting the vehicle with accelerometers and speedometers,
I sat
in a Mercedes Benz and collected high speed data as it was rear
ended
by an SUV.

Bumper
height

I
developed a method to dynamically measure vehicle bumper height
while
braking in a collision/override case.

Bicycle
forks

By
failure analysis and testing I was able to reconstruct the
catastrophic failure of a bicycle fork. The force require to
fail the
fork was higher than the friction force that the weight of the
bicycle and rider could develop. I showed that when the front
wheel
locks, the rider and bicycle are accelerated upward generating a
large downward vertical force. This dynamic vertical force
combined
with the weight of the bicycle and rider was great enough to
develop
a friction force sufficient to fail the fork.

Falsework
collapse

The
falsework intended to support the construction of a concrete
freeway
overpass collapsed during assembly killing one worker and
injuring
several. By reviewing photographs of the failure, construction
documents and testimony of survivors, I was able to identify
the
instability that triggered the collapse.